The present invention relates to bonding technique of producing multi-layer plates by bonding plates such as optical substrate discs, flat glass plates, curved plates, lenses having curved surfaces or metal plates.
In the disc bonding system using liquid adhesive, prevention of voids (or bubbles) is one of the important problems. In an adhesive layer sandwiched between two substrate discs, there are formed voids, such as voids having diameters of about 0.1 mm or more and minute voids having diameters from 0.05 mm to 0.1 mm in spite of various measures for prevention.
It is an object of the present invention to provide plate bonding system and method advantageous for avoiding voids from adhesive layers.
According to the present invention, a plate bonding system for producing a bonded plate including first and second substrate plates and an adhesive layer sandwiched between the first and second plates, comprises:
a plate moving member for bringing the first and second plates closer to each other with the interposition of adhesive to produce the bonded plate; and
an electric circuit for producing an electric field in an interspace between the first and second plates.
A plate bonding method according to the present invention comprises:
an overlapping step of overlapping first and second plates by bringing the first and second plates closer to each other with the interposition of adhesive to produce the bonded plate; and
an electric field producing step of producing an electric field in an interspace between the first and second plates during a period in the overlapping step.